Tony

Gone

SharkSkin

AWESOME! WTG Tony!

GoRideSno

Awsome post as usual Tony.
I agree on both items.
You'll gain 20+hp once you get the mixture right. When you bought the Bell regulator it came with a small restrictor that fits inside the vac line going to the regulator. Are you using this? You may want to put it in if not. It will help give a lower rate of gain. Sometimes it's necessary other times not. 12.5 to 13.5 will give you max power but I suggest 11.5 as a safe mixture. Did you use the record feature on the LM-1?
Have you tensioned your belt since Srktbrfst? It was definately loose there. They will go through a break-in period for the first few miles. I've sent you one of the static type tensioners that will help too since you can't get behind the dynamic style bracket with your oil breather setup. With the belt tightened and the fuel right you'll be seeing 400-410.

I'm guessing you'll get 12.8-12.9 on the Kumhos without any tuning provided you get a little practice between now and then or some practice there.

With 5.5 psi and 376RWHP you are making over 22rwhp per psi of boost with your setup. This is very good and beyond the upper limit of what is supposed to be possible by adding forced induction. The "max" is 6.8% original HP per psi. You've got more than 6.8% per psi boost with quite a bit left on the table. My 400rwhp dyno was beyond the 6.8% mark too. Thank you Dr Porsche for these wonderfull heads and S4 "big gulp" cams.
Excellent Job. I look forward to the next report.

Andy K

fast951

Great numbers. I wonder why only a few are using a PiggyBack to handle both fuel and timing? Using fuel pressure to richen the mixture is ok, but you cannot adjust the mixture based on load/rpm..

GoRideSno

Fast951,
A big advantage to the positive a displacement type SC is that the stock power curve matches the stock power curve due to a constant level of boost throughout the rpm range. So getting the fuel right throughout the rpm range is not tricky as with turbos and such that have a variable ammount of boost throughout the rpm range. In general l've seen a variance of less than 1 AFR point throughout the rpm range by using only fuel pressure referenced by boost. Not to say using a piggy back or stand alone is not a good idea, it sure is. There is always a better way.

Andy K

Shane

Tony great job!!

Just me but I would feel safe with 12.0:1 air/fuel ratio. Plus with that corrected and the slipping belt you would be seeing 400hp/400tq like Andy.

fast951

Andy, does the MAF maxes out with the supercharger? I recall on my S4 the MAF voltage was 2.5-7v or so.. What voltage does it reach with 7psi boost.

Don't you guys need to pull timing back? Or you just use the relaxed factory timing and let the knock sensors handle any knock?

GoRideSno

Shane,
Is that you in your avatar?

Tony,
Are you using the 66mm pulley?


Andy K

GoRideSno

fst951,
I haven't maxed out the MAF yet. IIRC the MAF is good for over 500rwhp so I haven't given it much thought yet but probably will soon.

You've stated my theory on the timing.

Any input is welcome.


Andy K

Shane

Yes, see this thread for why----->OT thread

fast951

Andy, It has been a while since i looked at the timing values for the S4, mine was a Euro 5-spd no O2 sensor. Not sure if the timing was any different than US spec.

I wonder if you will be able to run more boost by pulling timing back? A friend has a 928S4 that I will help him tune once he installs the supercharger. I guess we can experiment a bit on the dyno.

Does your car make more HP when using race gas vs. pump gas?

Nicole

Congratulations! This is very impressive!

Gosh, how could you ever NOT want to be rich?

pman928

Thank you Tony! You are my inspiration! I really appreciate all your sharing of info. I love your web site. Did you document your supercharger install? How do you like how your car performs?

GoRideSno

Fst951

I've only used race gas at the track and only because it was 105 degrees. So I haven't done an actual comparison. If your're asking to see if maybe the timing was retarding with pump gas, I really don't think so at all. I've breifly had the car at over 10psi and Shane has been to the track on pump gas, 10+ psi and no knock sensors, sucking hot air from under the hood and over 170+mph whith virtually the same setup and no problems. The only difference is that he is using my old Whipple 2.3 and we are now using the Autorotor 2.2. They are virtually the same.
The S4 heads and cams will give less boost but more HP per psi/boost that the 85-85 heads and cams will BTW.

Andy K

mspiegle

I'll probably be the first one to use a piggyback. I've got an SMT6 sitting around, and I just bought all of the goods (shrink wrap and harness connectors) so I'll be installing it shortly. Unfortunately, it won't do me any good with my current 4.5PSI, so I won't be able to put it to good use until I get a twinscrew setup.